The problem of recurrent female urinary incontinence, or the inability to control urination, is a major and debilitating one affecting millions of women in the United States alone. One particular type that frequently occurs in women is stress urinary incontinence, which is precipitated by coughing, straining, or heavy lifting. Mild cases may be treated by exercises involving tightening and relaxing of the perineal and gluteal muscles or by sympathomimetic drug therapy. Severe cases, however, may require surgery to correct the underlying anatomic defect. It is this surgical correction which is the subject of the present invention.
In general, continence is considered to be a function of urethral support and coaptation. For coaptation to successfully prevent or cure incontinence, the urethra must be supported and stabilized in its normal anatomic position. The female's natural support system for the urethra is a hammock-like supportive layer composed of endopelvic fascia, the anterior vaginal wall, and a distal attachment to the pubic bone. Weakening and elongation of the pubourethral ligaments and the arcus tendineus fascia pelvis, weakening of the endopelvic fascia and pubourethral prolapse of the anterior vaginal wall, and their complex interaction with intraabdominal forces are all suspected to play a role in the loss of pelvic support for the urethra and subsequent hypermobility to an unnaturally low non-anatomic position, leading to urinary incontinence.
Many procedures have been devised to treat urinary incontinence with the goal of elevating the neck of the bladder to return it to a higher retropubic position. Some involve the creation of a compensatory pubovaginal sling through a variety of needle suspension procedures; others employ a suburethral mesh to act as a compensatory suburethral sling to avoid the possibility that the sutures used in the needles suspension procedures will easily tear.
Many of the needle suspension procedures involve placing sutures in the endopelvic fascia or the anterior vaginal wall on either side of the urethra and attaching them to fixation sites such as bone and soft tissue. Alternatively, the sutures are attached to artificial anchors placed within the pelvis, at the superior border of the pubis, or rectus abdominus fascia. A major problem with this type of procedure is that the very fascial and muscular support structures that are sutured for support are often stretched, damaged, or otherwise deficient to begin with, and remain so after the procedure. It is therefore difficult to employ them successfully as reinforcements for surgical repair.
The pubovaginal sling procedure, in which a mesh is placed under the urethra to provide elevation and support of the urethra and bladder neck, has enjoyed an excellent surgical success rate. It is generally preferable for more complicated cases of recurrent genuine stress urinary incontinence, particularly in patients who have failed prior surgery, who are obese, or whose lifestyles involve heavy lifting and accompanying increased intraabdominal pressure. However, problems with voiding disfunction and urinary retention, detrusor instability, and infection and erosion of sling materials that can lead to urethrovesical and vesicovaginal fistulas are cause for concern. Additionally, this procedure is more technically challenging, presents greater blood loss, longer operative time, and a prolonged postoperative recovery.
These techniques use a variety of attachment sites for bladder neck and urethral support, such as the superior portion of the pubis, Cooper's ligament, or rectus abdominus fascia. This results in placement of the urethra in an unnaturally high position with respect to its normal anatomical retropubic position so that problems with voiding and urinary retention frequently arise after the procedure. Further, this abnormal positioning of the urethra in conjunction with failure of the supporting tissues and poor surgical technique have often led to a recurrence of incontinence since all of these operations create a compensatory abnormality rather than restoring the normal anatomy.
A related difficulty that contributes to the unnatural positioning of the urethra is that some attachment sites, such as the rectus abdominus fascia, require very long sutures and accompanying difficulty in achieving the proper tension in the sutures. This can result in increased lateral movement and momentum of the support structures or mesh sling when they are moved due to intraabdominal pressures.
The present invention addresses and corrects these and other difficulties by affecting the continence mechanism directly and providing a predictable and lasting permanent cure for the problem of recurrent female urinary incontinence.
It has been found that the key site for control of continence has not been heretofore addressed. It has further been found that the urethral hypermobility observed in most incontinent patients is caused by a lax or torn arcus tendineus facia pelvis attachment at its origin near the anterior levator arch in the immediate retropubic position at the site of the pubourethral ligaments. Repair and reinforcement of this area to stabilize the urethra in its normal position may be equally important as repair of the endopelvic facia. Therefore, the key site for control of continence is the paraurethral attachments of the pubourethral ligaments to the sides of the urethra at the intermediate 60% of the urethral length. This is simulated through the employment of a mesh sling system which supports this site and restores the bladder neck and urethra to their normal anatomic retropubic position. Additionally, when placed in this position, the lateral sides of the mesh serve to act as pubourethral ligaments which help to prevent undue descent of the urethra.
It has also been found that although the superior portion of the pubic bone is a functional and secure fixation site for incontinence repair, a key to restoring the urethra to its normal anatomical position is using the posterior/inferior border of the pubic bone, not the superior portion, as the attachment sites for the mesh sling system. Proper tensioning of the mesh sling system is made easier by using this portion of the pubic bone as the attachment site, due in part to the fact that shorter sutures and an innovative mesh suturing pattern is used. This serves to avoid the problems heretofore discussed associated with an improperly high retropubic positioning of the urethra.